Apparatus and System for Swing Adsorption Processes

ABSTRACT

Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve performing dampening for fluctuations in the streams conducted away from the adsorbent bed unit. The process may be utilized for swing adsorption processes, such as rapid cycle TSA and/or rapid cycle PSA, which are utilized to remove one or more contaminants from a gaseous feed stream.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.16/252,975 filed Jan. 21, 2019, which claims the priority benefit ofU.S. Provisional Application No. 62/621,246 filed Jan. 24, 2018,entitled APPARATUS AND SYSTEM FOR SWING ADSORPTION PROCESSES, theentirety of which is incorporated by reference herein.

FIELD

The present techniques relate to a method and system associated withswing adsorption processes used in conditioning streams for downstreamprocessing. In particular, the method and system involves performingswing adsorption processes to dampen the temperature swing in theproduct stream to within acceptable limits for the downstream process.

BACKGROUND

Gas separation is useful in many industries and can typically beaccomplished by flowing a mixture of gases over an adsorbent materialthat preferentially adsorbs one or more gas components while notadsorbing one or more other gas components. The non-adsorbed componentsare recovered as a separate product.

One particular type of gas separation technology is swing adsorption,such as temperature swing adsorption (TSA), pressure swing adsorption(PSA), partial pressure swing adsorption (PPSA), rapid cycle temperatureswing adsorption (RCTSA), rapid cycle pressure swing adsorption (RCPSA),rapid cycle partial pressure swing adsorption (RCPPSA), and not limitedto but also combinations of the fore mentioned processes, such aspressure and temperature swing adsorption. As an example, PSA processesrely on the phenomenon of gases being more readily adsorbed within thepore structure or free volume of an adsorbent material when the gas isunder pressure. That is, the higher the gas pressure, the greater theamount of readily-adsorbed gas adsorbed. When the pressure is reduced,the adsorbed component is released, or desorbed from the adsorbentmaterial.

The swing adsorption processes (e.g., PSA and/or TSA) may be used toseparate gases of a gas mixture because different gases tend to fill themicropore of the adsorbent material to different extents. For example,if a gas mixture, such as natural gas, is passed under pressure througha vessel containing an adsorbent material that is more selective towardscarbon dioxide than it is for methane, at least a portion of the carbondioxide is selectively adsorbed by the adsorbent material, and the gasexiting the vessel is enriched in methane. When the adsorbent materialreaches the end of its capacity to adsorb carbon dioxide, it isregenerated by reducing the pressure, thereby releasing the adsorbedcarbon dioxide. Then, the adsorbent material is typically purged andrepressurized prior to starting another adsorption cycle.

The swing adsorption processes typically involve adsorbent bed units,which include adsorbent beds disposed within a housing and configured tomaintain fluids at various pressures for different steps in a cyclewithin the unit. These adsorbent bed units utilize different packingmaterial in the bed structures. For example, the adsorbent bed unitsutilize checker brick, pebble beds or other available packing. As anenhancement, some adsorbent bed units may utilize engineered packingwithin the bed structure. The engineered packing may include a materialprovided in a specific configuration, such as a honeycomb, ceramic formsor the like.

Further, various adsorbent bed units may be coupled together withconduits and valves to manage the flow of fluids through the cycle.Orchestrating these adsorbent bed units involves coordinating the stepsin the cycle for each of the adsorbent bed units with other adsorbentbed units in the system. A complete cycle can vary from seconds tominutes as it transfers a plurality of gaseous streams through one ormore of the adsorbent bed units.

A challenge with rapid cycle processes is the temperature,compositional, and pressure pulse associated with the transition ofstreams through the adsorbent beds between the various steps in a cycle.For example, swing adsorption processes for deep dehydration used withLNG applications, a temperature swing step may be used to regenerate aspent adsorbent bed after an adsorption step. However, this heating ofthe adsorbent bed may rely upon the feed stream to cool the adsorbentbed. As a result, the feed steam may cool the adsorbent bed during theinitial portion of the adsorption step. As a result, the product streamfrom the adsorbent bed may involve temperature swings. These temperaturefluctuations are problematic for the liquefaction process.

In addition to the temperature fluctuations, compositional variationsmay also be present from the swing adsorption processes. For example,the composition variation in purge gas leaving an adsorbent bed duringregeneration. The concentration of the contaminant initially increases,as the adsorbent bed is being rapidly regenerated, before decreasing.Furthermore, the temperature of this gas stream gradually increasesduring the step. Certain downstream processes may need to have thecomposition variations and/or temperature fluctuations within specificlevels to operate properly.

Accordingly, there remains a need in the industry for apparatus,methods, and systems that provided enhancements to managing temperature,compositional, and pressure pulses associated with hydrocarbon recoveryprocesses. In particular, a need exists for enhancements to temperature,compositional, and pressure pulses in rapid cycle swing adsorptionprocesses.

SUMMARY OF THE INVENTION

In one embodiment, a process for removing contaminants from a gaseousfeed stream with a swing adsorption process is described. The processcomprising: a) performing an adsorption step, wherein the adsorptionstep comprises passing a gaseous feed stream through an adsorbent bedunit to remove one or more contaminants and produce a product stream; b)interrupting the flow of the gaseous feed stream; c) performing aheating step, wherein the heating step comprises passing a heatingstream through the adsorbent bed unit to remove one or more contaminantsfrom the adsorbent bed unit; d) performing a cooling step, wherein thecooling step comprises lessening the temperature of an adsorbentmaterial in the adsorbent bed unit by passing a cooling stream throughthe adsorbent bed unit; and e) repeating the steps a) to d) for at leastone additional cycle in the swing adsorption process.

In one or more embodiments, the process includes one or moreenhancements. The process may include wherein the cycle duration is fora period greater than 1 second and less than 600 seconds; wherein thegaseous feed stream is a hydrocarbon containing stream having greaterthan one volume percent hydrocarbons based on the total volume of thefeed stream; wherein the gaseous feed stream comprises hydrocarbons andCO₂, wherein the CO₂ content is from about 200 parts per million volumeto about 2% volume of the gaseous feed stream; wherein the swingadsorption process is configured to lower the carbon dioxide (CO₂) levelto less than 50 parts per million; passing the product stream to adownstream process; wherein the downstream process is a liquefiednatural gas (LNG) process that comprises an LNG process unit; whereinthe downstream process is a cryogenic natural gas liquefaction (NGL)process having a NGL process unit; wherein the cycle duration is greaterthan 2 seconds and less than 180 seconds; wherein the cooling stream ispassed from the adsorbent bed unit to a conditioning unit; and theconditioned stream is passed from the conditioning unit to anotheradsorbent bed unit as the heating stream; wherein the heating stream ispassed in a direction that is counter-current to the direction that thefeed stream is passed; and the cooling stream is passed in a directionthat is counter-current to the direction that the feed stream is passed;further comprising splitting a purge stream into the heating stream andthe cooling stream; wherein the cooling stream is passed in a directionthat is co-current to the direction that the feed stream is passed; andthe heating stream is passed in a direction that is counter-current tothe direction that the feed stream is passed; further comprisingdetermining whether the product stream is within acceptable temperaturelimits; wherein the acceptable temperature limits include the productstream having temperatures within 50° F. of feed temperature of thegaseous feed stream; wherein the acceptable temperature limits includethe product stream having temperatures within 25° F. of feed temperatureof the gaseous feed stream; wherein the acceptable temperature limitsinclude the product stream having temperatures within 10° F. of feedtemperature of the gaseous feed stream; wherein the swing adsorptionprocess is a rapid cycle temperature swing adsorption process; and/orwherein the swing adsorption process is a rapid cycle temperature swingadsorption process and a rapid cycle temperature swing adsorptionprocess.

In another embodiment, a cyclical swing adsorption system is described.The system may comprise: a plurality of adsorbent bed units coupled to aplurality of manifolds, each of the adsorbent bed units is configured topass different streams through the adsorbent bed unit between two ormore steps in a swing adsorption cycle and each of the adsorbent bedunits is configured to remove one or more contaminants from a feedstream to form a product stream and wherein each of the adsorbent bedunits comprise: a housing; an adsorbent material disposed within thehousing; a plurality of valves, wherein at least one of the plurality ofvalves is associated with one of the plurality of manifolds and isconfigured to manage fluid flow along a flow path extending between therespective manifold and the adsorbent material; and wherein the cyclicalswing adsorption system is configured to dampen one or more oftemperature, compositional, and pressure pulses associated with thetransition of different streams through the adsorbent beds between thetwo or more steps in the swing adsorption cycle.

In one or more embodiments, the system includes one or moreenhancements. The cyclical swing adsorption system may include whereinthe plurality of manifolds comprise a feed manifold configured to passthe feed stream to the plurality of adsorbent bed units during anadsorption step, a product manifold configured to pass the productstream from the plurality of adsorbent bed units during the adsorptionstep, a purge manifold configured to pass a purge stream to theplurality of adsorbent bed units during a regeneration step, a purgeproduct manifold configured to pass a purge product stream from theplurality of adsorbent bed units during the regeneration step, eachmanifold of the plurality of manifolds is associated with one swingadsorption process step of a plurality of swing adsorption processsteps; wherein the plurality of manifolds comprise a cooling manifoldconfigured to pass a cooling stream to the plurality of adsorbent bedunits during a cooling step, a cooling product manifold configured topass a cooling product stream from the plurality of adsorbent bed unitsduring the cooling step; wherein the plurality of manifolds comprise afeed manifold configured to pass the feed stream to the plurality ofadsorbent bed units during an adsorption step, a product manifoldconfigured to pass the product stream from the plurality of adsorbentbed units during the adsorption step, a purge manifold configured tosplit the purge stream into a first purge stream configured to pass tothe plurality of adsorbent bed units during a heating step and a secondpurge stream configured to pass to the plurality of adsorbent bed unitsduring a cooling step, a first purge product manifold configured to passa first purge product stream from the plurality of adsorbent bed unitsduring the heating step, and a second purge product manifold configuredto pass a second purge product stream from the plurality of adsorbentbed units during the cooling step; a heating unit disposed upstream ofthe split in the purge manifold, wherein the heating unit is configuredto increase the temperature of the first purge stream prior to passingthe plurality of adsorbent bed units during a heating step; wherein theplurality of manifolds comprise a feed manifold configured to pass thefeed stream to the plurality of adsorbent bed units during an adsorptionstep, a product manifold configured to pass the product stream from theplurality of adsorbent bed units during the adsorption step, a purgemanifold configured to pass a cooling stream to the plurality ofadsorbent bed units during a cooling step and a cooling purge productmanifold configured to pass a cooling purge product stream from theplurality of adsorbent bed units during the cooling step and configuredto pass a heating stream to another of the plurality of adsorbent bedunits during a heating step, and a second purge product manifoldconfigured to pass a heating purge product stream from the plurality ofadsorbent bed units during the heating step; a heating unit associatedwith the cooling purge product manifold and configured to heat thecooling purge product stream to form the heating stream; a liquefiednatural gas (LNG) process that comprises an LNG process unit and isconfigured to receive the product stream; a cryogenic natural gasliquefaction (NGL) process having a NGL process unit and is configuredto receive the product stream; a dampening system in fluid communicationwith the plurality of adsorbent bed units and configured to lessen oneor more of temperature fluctuations, compositional fluctuations, and anycombination thereof associated with the transition of the differentstreams through the adsorbent beds between the two or more steps in theswing adsorption cycle; wherein the dampening system comprises a heatexchanger configured to provide sufficient thermal capacitance to dampentemperature pulses in the product stream; wherein the dampening systemcomprises an accumulator configured to manage compositions of theproduct stream; wherein the dampening system comprises a mixing unitconfigured to manage compositions of the product stream; wherein theplurality of manifolds further comprise a blowdown manifold configuredto pass a blowdown stream from the plurality of adsorbent bed unitsduring a blowdown step; wherein the plurality of valves comprise one ormore poppet valves; and/or wherein the plurality of adsorbent bed unitsare configured to operate at pressures between 0.1 bar absolute (bara)and 100 bara.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other advantages of the present disclosure may becomeapparent upon reviewing the following detailed description and drawingsof non-limiting examples of embodiments.

FIG. 1 is a three-dimensional diagram of the swing adsorption systemwith six adsorbent bed units and interconnecting piping in accordancewith an embodiment of the present techniques.

FIG. 2 is a diagram of a portion of an adsorbent bed unit havingassociated valve assemblies and manifolds in accordance with anembodiment of the present techniques.

FIG. 3 is an exemplary flow chart for performing an external startupmode of a swing adsorption process in accordance with an embodiment ofthe present techniques.

FIG. 4 is an exemplary diagram of steps in a swing adsorption process inaccordance with an embodiment of the present techniques.

FIG. 5 is another exemplary diagram of steps in a swing adsorptionprocess in accordance with an embodiment of the present techniques.

FIG. 6 is an exemplary diagram of product gas temperature from a swingadsorption process.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise explained, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which this disclosure pertains. The singular terms“a,” “an,” and “the” include plural referents unless the context clearlyindicates otherwise. Similarly, the word “or” is intended to include“and” unless the context clearly indicates otherwise. The term“includes” means “comprises.” All patents and publications mentionedherein are incorporated by reference in their entirety, unless otherwiseindicated. In case of conflict as to the meaning of a term or phrase,the present specification, including explanations of terms, control.Directional terms, such as “upper,” “lower,” “top,” “bottom,” “front,”“back,” “vertical,” and “horizontal,” are used herein to express andclarify the relationship between various elements. It should beunderstood that such terms do not denote absolute orientation (e.g., a“vertical” component can become horizontal by rotating the device). Thematerials, methods, and examples recited herein are illustrative onlyand not intended to be limiting.

As used herein, “stream” refers to fluid (e.g., solids, liquid and/orgas) being conducted through various equipment. The equipment mayinclude conduits, vessels, manifolds, units or other suitable devices.

As used herein, “conduit” refers to a tubular member forming a channelthrough which something is conveyed. The conduit may include one or moreof a pipe, a manifold, a tube or the like.

The provided processes, apparatus, and systems of the present techniquesmay be used in swing adsorption processes that remove contaminants (CO₂,H₂O, and H₂S) from feed streams, such as hydrocarbon containing streams.As may be appreciated and as noted above, the hydrocarbon containingfeed streams may have different compositions. For example, hydrocarbonfeed streams vary widely in amount of acid gas, such as from severalparts per million acid gas to 90 volume percent (vol. %) acid gas.Non-limiting examples of acid gas concentrations from exemplary gasreserves sources include concentrations of approximately: (a) 4 ppm H₂S,2 vol. % CO₂, 100 ppm H₂O (b) 4 ppm H₂S, 0.5 vol. % CO₂, 200 ppm H₂O (c)1 vol. % H₂S, 2 vol. % CO₂, 150 ppm H₂O, (d) 4 ppm H₂S, 2 vol. % CO₂,500 ppm H₂O, and (e) 1 vol. % H₂S, 5 vol. % CO₂, 500 ppm H₂O. Further,in certain applications the hydrocarbon containing stream may includepredominately hydrocarbons with specific amounts of CO₂ and/or water.The gaseous feed stream utilized in the processes herein comprises, orconsists essentially of, a hydrocarbon containing stream. For example,the gaseous feed stream may have greater than 0.00005 volume percent CO₂based on the total volume of the gaseous feed stream and less than 2volume percent CO₂ based on the total volume of the gaseous feed stream;or less than 10 volume percent CO₂ based on the total volume of thegaseous feed stream. In other embodiments, the gaseous feed stream mayhave a CO₂ content from about 200 parts per million volume to about 2%volume based on the gaseous feed stream. The processing of feed streamsmay be more problematic when certain specifications have to besatisfied.

The removal of contaminants may be performed by swing adsorptionprocesses to prepare the stream for further downstream processing, suchas NGL processing and/or LNG processing. For example, natural gas feedstreams for liquefied natural gas (LNG) applications have stringentspecifications on the CO₂ content to ensure against formation of solidCO₂ at cryogenic temperatures. The LNG specifications may involve theCO₂ content to be less than or equal to 50 ppm. Such specifications arenot applied on natural gas streams in pipeline networks, which mayinvolve the CO₂ content up to 2 vol. % based on the total volume of thegaseous feed stream. As such, for LNG facilities that use the pipelinegas (e.g., natural gas) as the raw feed, additional treating orprocessing steps are utilized to further purify the stream. Further, thepresent techniques may be used to lower the water content of the streamto less than 0.1 ppm. Exemplary swing adsorption processes andconfigurations may include U.S. Patent Application Publication Nos.US2017/0056814, US2017/0113175 and US2017/0113173, and U.S. Pat. Nos.10,080,991, 10,124,286, 10,080,992 and 10,040,022, which are eachincorporated by reference herein.

The present techniques provide configurations and processes that areutilized to enhance swing adsorption processes. As noted above, rapidcycle pressure and temperature swing adsorption processes may be used todehydrate streams and/or remove low-level CO₂. To manage thetemperature, compositional, and pressure pulses associated with thetransition of streams within the adsorbent beds between the steps in thecycle, the present techniques may include additional steps ormechanisms. The present techniques provide a method to minimize thetemperature and/or compositional fluctuations in a stream beingconducted away from the rapid cycle swing adsorption process. In otherconfigurations, a system is used to minimize the temperature and/orcompositional fluctuations in one or more streams being conducted awayfrom the rapid cycle swing adsorption process units.

For example, one configuration may include using a dampening system,which is disposed downstream of the swing adsorption bed units andupstream of the downstream processing units, such as a LNG processingunit. The dampening system may be configured to dampen the respectivefluctuations. By way of example, the dampening system may include a heatexchanger and/or a piping network that may be used to provide sufficientthermal mass to provide the thermal capacitance to dampen any associatedtemperature pulses in the product stream.

In yet another example, the dampening system may include an accumulatormay be used to manage the composition of the stream being conducted awayfrom the adsorbent bed unit. The accumulator may be disposed downstreamof the swing adsorption bed units and upstream of the downstreamprocessing units, such as a LNG processing unit. As a specific example,the purge gas being conducted away from the adsorbent bed that is usedin the regeneration step. The concentration of the contaminants in thepurge product stream may initially be higher and then decrease duringthe later portion of the purge step. The accumulator may be used to mixor intermingle the purge product stream to manage the composition into amore uniform distribution of contaminants. Furthermore, the dampeningsystem may include a heat exchanger and an accumulator. The temperatureof the purge gas stream may gradually increases during the purge step.If the purge stream is to be provided to a downstream system, such as agas turbine, the dampening system may manage the pulses to provide thatthe gas wobbe index is within acceptable limits.

In another configuration, the swing adsorption process may include acooling step to manage the temperature of the adsorbent bed andresulting product stream. The cooling step may adjust the temperature(e.g., cool) the adsorbent bed down after a regeneration step. As such,the product stream being conducted away from the adsorbent bed unit maybe at a temperature within acceptable limits. For example, in an LNGdehydration system, a cooling step may be used after the regenerationstep (e.g., a temperature swing step), which may be used to regenerate aspent adsorbent bed. By using the cooling step, the feed stream may notbe relied upon to adjust the temperature of the adsorbent bed during theswing adsorption cycle because the cooling step may be used to dampenthe temperature fluctuations of the resulting product stream from theadsorbent bed unit. As a result of the cooling step, the product gastemperature of the product stream may be managed within a temperaturethreshold that may enhance the downstream processing of the productstream. Accordingly, the product stream may be passed to theliquefaction process within acceptable temperature limits. By way ofexample, the acceptable temperature limits may include product streamsfor the swing adsorption system having temperatures within 50° F. offeed temperature for the swing adsorption system, within 25° F. of feedtemperature for the swing adsorption system, or within 10° F. of feedtemperature for the swing adsorption system.

By way of example, conventional processes, such as molecular sieveprocesses, regenerate a spent molecular sieve bed by heating the bed toremove contaminants followed by cooling the molecular sieve bed toprepare the molecular sieve bed for adsorption. These steps are usuallydone by the same regeneration gas stream that is initially heated toheat the molecular sieve bed and later not heated to cool the molecularsieve bed. In such a configuration, the heating and cooling steps arenot continuous (e.g., at least one bed is being cooled and one bed isbeing heated simultaneously at any instant).

For LNG applications, the purge gas stream may be sourced from end-flashcompression, boil-off-gas compression, directly from the feed gas or acombination thereof. The purge stream may serve as the fuel gas streamand is limited in flow rate. To use the same stream for cooling andheating, two configurations may be utilized. The first configuration maysplits the available purge stream into a cool stream and a heating fordifferent adsorbent beds. While no recycling is performed, the coolingand heating are performed continuously (e.g., at least one adsorbent bedis being cooled and one bed is being heated at any instant). If theavailable flow rate is not sufficient, then the stream may be recycled.However, the stream may be recycled, such that the heating streamremains contaminant free (e.g., during the cooling step contaminantsfrom the adsorbent bed do not move into the purge stream because of theflow direction being co-current to the feed flow direction). These stepsare continuous, which is beneficial for RCPSA and/or RCPSTA cyclesensuring steady flows through various streams. The recycling provides afew additional aspects, such as a method to simultaneously control theproduct temperature and recover heat internally (e.g., reduced overallheat required to regenerate the bed).

In yet another configuration, the present techniques may utilize acooling step in the swing adsorption process. The purge gas stream,which may be at or near ambient temperatures, may be split into twostreams. The first stream may be heated and used to regenerate theadsorbent bed, while the second stream may be used to cool a recentlyregenerated adsorbent bed. The first and second streams may beintroduced in a counter-current direction relative to the feed stream,which may performed to maintain the dryness of the product end of theadsorbent bed throughout the regeneration and cooling steps of the swingadsorption cycle.

Further, in another configuration, the present techniques may utilize adifferent cooling step in the swing adsorption process. In thisconfiguration, the purge stream, which may be at or near ambienttemperatures, is first passed in a co-current direction relative to thedirection of the feed stream to cool a recently regenerated adsorbentbed. The cooling step may lessen the temperature of the adsorbent bed,while recovering some of the heat in the adsorbent bed. The resultinggas stream is then heated and introduced to a spent adsorbent bed toregenerate the adsorbent bed. This configuration has the additionalbenefit of recovering some of the heat from the regeneration step of theswing adsorption cycle.

In still yet another configuration, additional dampening may be achievedby operating multiple adsorbent beds out of sequence on feed. Forexample, a new adsorbent bed may be introduced on the feed stream, whilea different adsorbent bed is already operational and producing productat nearly the feed temperature.

In other configurations, the present techniques may involve temperatureswing dampening. The method of managing the temperature fluctuationsand/or compositional fluctuations in the purge gas stream may use acombination of heat exchangers and mixing drums. The heat exchangers mayprovide a method to cool the gas stream to a specific temperature range.As the purge stream may be a small flow rate in comparison the productstream, the size of the heat exchanger may be relatively small.Furthermore, in performing dehydration, the heat exchanger may be usedto condense excess water in the purge stream. The mixing drum providesthe proper residence time to manage the compositional pulses, such thatthe gas stream leaving the mixing drum is more uniform in composition.

The present techniques may be a swing adsorption process, andspecifically a rapid cycle adsorption process. The present techniquesmay include some additional equipment, such as one or more conduitsand/or one or more manifolds that provide a fluid path for the coolingstep and/or dampening system. In addition, other components andconfigurations may be utilized to provide the swing adsorption process,such as rapid cycle enabling hardware components (e.g., parallel channeladsorbent bed designs, rapid actuating valves, adsorbent bedconfigurations that integrate with other processes). Exemplary swingadsorption processes and configurations may include U.S. PatentApplication Publication Nos. US2017/0056814, US2017/0113175 andUS2017/0113173, and U.S. Pat. Nos. 10,080,991, 10,124,286, 10,080,992and 10,040,022, which are each incorporated by reference herein.

In one or more configurations, a swing adsorption process may includeperforming various steps. For the example, the present techniques may beused to remove contaminants from a gaseous feed stream with a swingadsorption process, which may be utilized with one or more downstreamprocesses. The process comprising: a) performing a heating step, whereinthe heating step comprises passing a heating stream through theadsorbent bed unit to remove one or more contaminants from the adsorbentbed unit (e.g., a heated purge step that comprises passing a heatedpurge stream through an adsorbent bed unit to remove contaminants froman adsorbent bed within a housing of the adsorbent bed unit to form apurge product stream, which may be a heated purge stream); b) performinga cooling step, wherein the cooling step may comprise passing coolingstream through an adsorbent bed unit to remove lessen the temperature ofthe adsorbent bed within a housing of the adsorbent bed unit to lessenthe temperature of the adsorbent bed prior to the one or more adsorptionsteps; c) performing one or more adsorption steps, wherein each of theone or more adsorption steps comprise passing a gaseous feed streamthrough an adsorbent bed unit having an adsorbent bed to separatecontaminants from the gaseous feed stream to form a product stream. Inaddition, the method may include determining whether the product streamand/or purge stream is within a temperature specification and/orcomposition specification; d) if the product stream and/or purge streamis within the respective specification (e.g., is below a certainthreshold), passing the product stream to a downstream process; and e)if the product stream is not within the specification (e.g., above acertain threshold), passing the product stream and/or purge streamthrough the dampening system.

In other certain embodiments, the swing adsorption process may beintegrated with downstream equipment and processes. The downstreamequipment and processes may include control freeze zone (CFZ)applications, niotrogen removal unit (NRU), cryogenic NGL recoveryapplications, LNG applications, and other such applications. Each ofthese different applications may include different specifications forthe feed stream in the respective process. For example, a cryogenic NGLprocess or an LNG process and may be integrated with the respectivedownstream equipment. As another example, the process may involve H₂Oand/or CO₂ removal upstream of a cryogenic NGL process or the LNGprocess and may be integrated with respective downstream equipment.

In certain configurations, the system utilizes a combined swingadsorption process, which combines TSA and PSA, for treating of pipelinequality natural gas to remove contaminants for the stream to satisfy LNGspecifications. The swing adsorption process, which may be a rapid cycleprocess, is used to treat natural gas that is at pipeline specifications(e.g., a feed stream of predominately hydrocarbons along with less thanor equal to about 2% volume CO₂ and/or less than or equal to 4 ppm H₂S)to form a stream satisfying the LNG specifications (e.g., less than 50ppm CO₂ and less than about 4 ppm H₂S). The product stream, which may bethe LNG feed stream, may have greater than 98 volume percenthydrocarbons based on the total volume of the product stream, while theCO₂ and water content are below certain thresholds. The LNGspecifications and cryogenic NGL specifications may involve the CO₂content to be less than or equal to 50 ppm, while the water content ofthe stream may be less than 0.1 ppm.

Moreover, the present techniques may include a specific process flow toremove contaminants, such as CO₂ and/or water. For example, the processmay include an adsorbent step and a regeneration step, which form thecycle. The adsorbent step may include passing a gaseous feed stream at afeed pressure and feed temperature through an adsorbent bed unit toseparate one or more contaminants from the gaseous feed stream to form aproduct stream. The feed stream may be passed through the adsorbent bedin a forward direction (e.g., from the feed end of the adsorbent bed tothe product end of the adsorbent bed). Then, the flow of the gaseousfeed stream may be interrupted for a regeneration step. The regenerationstep may include one or more depressurization steps, one or more heatingsteps, and/or one or more purge steps. The depressurization steps, whichmay be or include a blowdown step, may include reducing the pressure ofthe adsorbent bed unit by a predetermined amount for each successivedepressurization step, which may be a single step and/or multiple steps.The depressurization step may be provided in a forward direction or maypreferably be provided in a countercurrent direction (e.g., from theproduct end of the adsorbent bed to the feed end of the adsorbent bed).The heating step may include passing a heating stream into the adsorbentbed unit, which may be a recycled stream through the heating loop and isused to heat the adsorbent material. The purge step may include passinga purge stream into the adsorbent bed unit, which may be a once throughpurge step and the purge stream may be provided in countercurrent flowrelative to the feed stream. The purge stream may be provided at a purgetemperature and purge pressure, which may include the purge temperatureand purge pressure being similar to the heating temperature and heatingpressure used in the heating step. Then, the cycle may be repeated foradditional streams. Additionally, the process may include one or morere-pressurization steps after the purge step and prior to the adsorptionstep. The one or more re-pressurization steps may be performed, whereinthe pressure within the adsorbent bed unit is increased with eachre-pressurization step by a predetermined amount with each successivere-pressurization step. The cycle duration may be for a period greaterthan 1 second and less than 600 seconds, for a period greater than 2second and less than 300 seconds, for a period greater than 2 second andless than 180 seconds, for a period greater than 5 second and less than150 seconds or for a period greater than 5 second and less than 90seconds.

In one or more embodiments, the present techniques can be used for anytype of swing adsorption process. Non-limiting swing adsorptionprocesses for which the present techniques may be used include pressureswing adsorption (PSA), vacuum pressure swing adsorption (VPSA),temperature swing adsorption (TSA), partial pressure swing adsorption(PPSA), rapid cycle pressure swing adsorption (RCPSA), rapid cyclethermal swing adsorption (RCTSA), rapid cycle partial pressure swingadsorption (RCPPSA), as well as combinations of these processes. Forexample, the preferred swing adsorption process may include a combinedpressure swing adsorption and temperature swing adsorption, which may beperformed as a rapid cycle process. Exemplary swing adsorption processesand configurations may include U.S. Patent Application Publication Nos.US2017/0056814, US2017/0113175 and US2017/0113173, and U.S. Pat. Nos.10,080,991, 10,124,286, 10,080,992, 10,040,022, 7,959,720, 8,545,602,8,529,663, 8,444,750, 8,529,662 and 9,358,493, which are each hereinincorporated by reference in their entirety.

Further still, in one or more configurations, a variety of adsorbentmaterials may be used to provide the mechanism for the separations.Examples include zeolite 3A, 4A, 5A, ZK4 and MOF-74. However, theprocess is not limited to these adsorbent materials, and others may beused as well.

In one configuration, a process for removing contaminants from a gaseousfeed stream with a swing adsorption process is described. The processmay comprise: a) performing an adsorption step, wherein the adsorptionstep comprises passing a gaseous feed stream through an adsorbent bedunit to remove one or more contaminants and produce a product stream; b)interrupting the flow of the gaseous feed stream; c) performing aheating step, wherein the heating step comprises passing a heatingstream through the adsorbent bed unit to remove one or more contaminantsfrom the adsorbent bed unit; d) performing a cooling step, wherein thecooling step comprises lessening the temperature of an adsorbentmaterial in the adsorbent bed unit by passing a cooling stream throughthe adsorbent bed unit; and e) repeating the steps a) to d) for at leastone additional cycle in the swing adsorption process.

In one or more configurations, the process may include one or moreenhancements. The process may include wherein the cycle duration is fora period greater than 1 second and less than 600 seconds; wherein thegaseous feed stream is a hydrocarbon containing stream having greaterthan one volume percent hydrocarbons based on the total volume of thefeed stream; wherein the gaseous feed stream comprises hydrocarbons andCO₂, wherein the CO₂ content is in the range of two hundred parts permillion volume and less than or equal to about 2% volume of the gaseousfeed stream; wherein the swing adsorption process is configured to lowerthe carbon dioxide (CO₂) level to less than 50 parts per million;passing the product stream to a downstream process; wherein thedownstream process is a liquefied natural gas (LNG) process thatcomprises an LNG process unit; wherein the downstream process is acryogenic natural gas liquefaction (NGL) process having a NGL processunit; wherein the cycle duration is greater than 2 seconds and less than180 seconds; wherein the cooling stream is passed from the adsorbent bedunit to a conditioning unit; and the conditioned stream is passed fromthe conditioning unit to another adsorbent bed unit as the heatingstream; wherein the heating stream is passed in a direction that iscounter-current to the direction that the feed stream is passed; and thecooling stream is passed in a direction that is counter-current to thedirection that the feed stream is passed; further comprising splitting apurge stream into the heating stream and the cooling stream; wherein thecooling stream is passed in a direction that is co-current to thedirection that the feed stream is passed; and the heating stream ispassed in a direction that is counter-current to the direction that thefeed stream is passed; further comprising determining whether theproduct stream is within acceptable temperature limits; wherein theacceptable temperature limits include the product stream havingtemperatures within 50° F. of feed temperature of the gaseous feedstream; wherein the acceptable temperature limits include the productstream having temperatures within 25° F. of feed temperature of thegaseous feed stream; wherein the acceptable temperature limits includethe product stream having temperatures within 10° F. of feed temperatureof the gaseous feed stream; wherein the swing adsorption process is arapid cycle temperature swing adsorption process; and/or wherein theswing adsorption process is a rapid cycle temperature swing adsorptionprocess and a rapid cycle temperature swing adsorption process.

In another configuration, a cyclical swing adsorption system isdescribed. The system may comprise: a plurality of adsorbent bed unitscoupled to a plurality of manifolds, each of the adsorbent bed units isconfigured to pass different streams through the adsorbent bed unitbetween two or more steps in a swing adsorption cycle and each of theadsorbent bed units is configured to remove one or more contaminantsfrom a feed stream to form a product stream and wherein each of theadsorbent bed units comprise: a housing; an adsorbent material disposedwithin the housing; a plurality of valves, wherein at least one of theplurality of valves is associated with one of the plurality of manifoldsand is configured to manage fluid flow along a flow path extendingbetween the respective manifold and the adsorbent material; and whereinthe cyclical swing adsorption system is configured to dampen one or moreof temperature, compositional, and pressure pulses associated with thetransition of different streams through the adsorbent beds between thetwo or more steps in the swing adsorption cycle.

In one or more configurations, the system may include one or moreenhancements. The cyclical swing adsorption system may include whereinthe plurality of manifolds comprise a feed manifold configured to passthe feed stream to the plurality of adsorbent bed units during anadsorption step, a product manifold configured to pass the productstream from the plurality of adsorbent bed units during the adsorptionstep, a purge manifold configured to pass a purge stream to theplurality of adsorbent bed units during a regeneration step, a purgeproduct manifold configured to pass a purge product stream from theplurality of adsorbent bed units during the regeneration step, eachmanifold of the plurality of manifolds is associated with one swingadsorption process step of a plurality of swing adsorption processsteps; wherein the plurality of manifolds comprise a cooling manifoldconfigured to pass a cooling stream to the plurality of adsorbent bedunits during a cooling step, a cooling product manifold configured topass a cooling product stream from the plurality of adsorbent bed unitsduring the cooling step; wherein the plurality of manifolds comprise afeed manifold configured to pass the feed stream to the plurality ofadsorbent bed units during an adsorption step, a product manifoldconfigured to pass the product stream from the plurality of adsorbentbed units during the adsorption step, a purge manifold configured tosplit the purge stream into a first purge stream configured to pass tothe plurality of adsorbent bed units during a heating step and a secondpurge stream configured to pass to the plurality of adsorbent bed unitsduring a cooling step, a first purge product manifold configured to passa first purge product stream from the plurality of adsorbent bed unitsduring the heating step, and a second purge product manifold configuredto pass a second purge product stream from the plurality of adsorbentbed units during the cooling step; a heating unit disposed upstream ofthe split in the purge manifold, wherein the heating unit is configuredto increase the temperature of the first purge stream prior to passingthe plurality of adsorbent bed units during a heating step; wherein theplurality of manifolds comprise a feed manifold configured to pass thefeed stream to the plurality of adsorbent bed units during an adsorptionstep, a product manifold configured to pass the product stream from theplurality of adsorbent bed units during the adsorption step, a purgemanifold configured to pass a cooling stream to the plurality ofadsorbent bed units during a cooling step and a cooling purge productmanifold configured to pass a cooling purge product stream from theplurality of adsorbent bed units during the cooling step and configuredto pass a heating stream to another of the plurality of adsorbent bedunits during a heating step, and a second purge product manifoldconfigured to pass a heating purge product stream from the plurality ofadsorbent bed units during the heating step; a heating unit associatedwith the cooling purge product manifold and configured to heat thecooling purge product stream to form the heating stream; a liquefiednatural gas (LNG) process that comprises an LNG process unit and isconfigured to receive the product stream; a cryogenic natural gasliquefaction (NGL) process having a NGL process unit and is configuredto receive the product stream; a dampening system in fluid communicationwith the plurality of adsorbent bed units and configured to lessen oneor more of temperature fluctuations, compositional fluctuations, and anycombination thereof associated with the transition of the differentstreams through the adsorbent beds between the two or more steps in theswing adsorption cycle; wherein the dampening system comprises a heatexchanger configured to provide sufficient thermal capacitance to dampentemperature pulses in the product stream; wherein the dampening systemcomprises an accumulator configured to manage compositions of theproduct stream; wherein the dampening system comprises a mixing unitconfigured to manage compositions of the product stream; wherein theplurality of manifolds further comprise a blowdown manifold configuredto pass a blowdown stream from the plurality of adsorbent bed unitsduring a blowdown step; wherein the plurality of valves comprise one ormore poppet valves; and/or wherein the plurality of adsorbent bed unitsare configured to operate at pressures between 0.1 bar absolute (bara)and 100 bara. The present techniques may be further understood withreference to the FIGS. 1 to 6 below.

FIG. 1 is a three-dimensional diagram of the swing adsorption system 100having six adsorbent bed units and interconnecting piping. While thisconfiguration is a specific example, the present techniques broadlyrelate to adsorbent bed units that can be deployed in a symmetricalorientation, or non-symmetrical orientation and/or combination of aplurality of hardware skids. Further, this specific configuration is forexemplary purposes as other configurations may include different numbersof adsorbent bed units.

In this system, the adsorbent bed units, such as adsorbent bed unit 102,may be configured for a cyclical swing adsorption process for removingcontaminants from feed streams (e.g., fluids, gaseous or liquids). Forexample, the adsorbent bed unit 102 may include various conduits (e.g.,conduit 104) for managing the flow of fluids through, to or from theadsorbent bed within the adsorbent bed unit 102. These conduits from theadsorbent bed units 102 may be coupled to a manifold (e.g., manifold106) to distribute the flow to, from or between components. Theadsorbent bed within an adsorbent bed unit may separate one or morecontaminants from the feed stream to form a product stream. As may beappreciated, the adsorbent bed units may include other conduits tocontrol other fluid steams as part of the process, such as purgestreams, depressurizations streams, and the like. In particular, theadsorbent bed units may include startup mode equipment, such as one ormore heating units (not shown), one or more external gas sourcemanifolds, which may be one of the manifolds 106) and one or moreexpanders, as noted further below, which is used as part of the startupmode for the adsorbent beds. Further, the adsorbent bed unit may alsoinclude one or more equalization vessels, such as equalization vessel108, which are dedicated to the adsorbent bed unit and may be dedicatedto one or more step in the swing adsorption process. The equalizationvessel 108 may be used to store the external stream, such as nitrogenfor use in the startup mode cycle.

As an example, which is discussed further below in FIG. 2, the adsorbentbed unit 102 may include a housing, which may include a head portion andother body portions, that forms a substantially gas impermeablepartition, an adsorbent bed disposed within the housing and a pluralityof valves (e.g., poppet valves) providing fluid flow passages throughopenings in the housing between the interior region of the housing andlocations external to the interior region of the housing. Each of thepoppet valves may include a disk element that is seatable within thehead or a disk element that is seatable within a separate valve seatinserted within the head (not shown). The configuration of the poppetvalves may be any variety of valve at patterns or configuration of typesof poppet valves. As an example, the adsorbent bed unit may include oneor more poppet valves, each in flow communication with a differentconduit associated with different streams. The poppet valves may providefluid communication between the adsorbent bed and one of the respectiveconduits, manifolds or headers. The term “in direct flow communication”or “in direct fluid communication” means in direct flow communicationwithout intervening valves or other closure means for obstructing flow.As may be appreciated, other variations may also be envisioned withinthe scope of the present techniques.

The adsorbent bed comprises a solid adsorbent material capable ofadsorbing one or more components from the feed stream. Such solidadsorbent materials are selected to be durable against the physical andchemical conditions within the adsorbent bed unit 102 and can includemetallic, ceramic, or other materials, depending on the adsorptionprocess. Further examples of adsorbent materials are noted furtherbelow.

FIG. 2 is a diagram of a portion of an adsorbent bed unit 200 havingvalve assemblies and manifolds in accordance with an embodiment of thepresent techniques. The portion of the adsorbent bed unit 200, which maybe a portion of the adsorbent bed unit 102 of FIG. 1, includes a housingor body, which may include a cylindrical wall 214 and cylindricalinsulation layer 216 along with an upper head 218 and a lower head 220.An adsorbent bed 210 is disposed between an upper head 218 and a lowerhead 220 and the insulation layer 216, resulting in an upper open zone,and lower open zone, which open zones are comprised substantially ofopen flow path volume. Such open flow path volume in adsorbent bed unitcontains gas that has to be managed for the various steps. The housingmay be configured to maintain a pressure from 0 bara (bar absolute) to150 bara within the interior region.

The upper head 218 and lower head 220 contain openings in which valvestructures can be inserted, such as valve assemblies 222 to 240,respectively (e.g., poppet valves). The upper or lower open flow pathvolume between the respective head 218 or 220 and adsorbent bed 210 canalso contain distribution lines (not shown) which directly introducefluids into the adsorbent bed 210. The upper head 218 contains variousopenings (not show) to provide flow passages through the inlet manifolds242 and 244 and the outlet manifolds 248, 250 and 252, while the lowerhead 220 contains various openings (not shown) to provide flow passagesthrough the inlet manifold 254 and the outlet manifolds 256, 258 and260. Disposed in fluid communication with the respective manifolds 242to 260 are the valve assemblies 222 to 240. If the valve assemblies 222to 240 are poppet valves, each may include a disk element connected to astem element which can be positioned within a bushing or valve guide.The stem element may be connected to an actuating means, such asactuating means (not shown), which is configured to have the respectivevalve impart linear motion to the respective stem. As may beappreciated, the actuating means may be operated independently fordifferent steps in the process to activate a single valve or a singleactuating means may be utilized to control two or more valves. Further,while the openings may be substantially similar in size, the openingsand inlet valves for inlet manifolds may have a smaller diameter thanthose for outlet manifolds, given that the gas volumes passing throughthe inlets may tend to be lower than product volumes passing through theoutlets.

In swing adsorption processes, the cycle involves two or more steps thateach has a certain time interval, which are summed together to be thecycle time or cycle duration. These steps include regeneration of theadsorbent bed following the adsorption step using a variety of methodsincluding pressure swing, vacuum swing, temperature swing, purging (viaany suitable type of purge fluid for the process), and combinationsthereof. As an example, a PSA cycle may include the steps of adsorption,depressurization, purging, and re-pressurization. When performing theseparation at high pressure, depressurization and re-pressurization(which may be referred to as equalization) may be performed in multiplesteps to reduce the pressure change for each step and enhanceefficiency. In some swing adsorption processes, such as rapid cycleswing adsorption processes, a substantial portion of the total cycletime is involved in the regeneration of the adsorbent bed. Accordingly,any reductions in the amount of time for regeneration results in areduction of the total cycle time. This reduction may also reduce theoverall size of the swing adsorption system.

Further, one or more of the manifolds and associated valves may beutilized as a dedicated flow path for one or more streams. For example,during the adsorption or feed step, the manifold 242 and valve assembly222 may be utilized to pass the feed gas stream to the adsorbent bed210, while the valve assembly 236 and manifold 256 may be used toconduct away the product stream from the adsorbent bed 210. During theregeneration or purge step, the manifold 244 and valve assembly 224 maybe utilized to pass the purge or heating stream to the adsorbent bed210, while the valve assembly 236 and manifold 256 may be used toconduct away the purge product stream from the adsorbent bed 210.Further, the manifold 254 and valve assembly 232 may be utilized for acooling stream, while the valve assembly 230 and manifold 252 may beused to conduct away the cooling product stream from the adsorbent bed210. As may be appreciated, the purge stream and/or cooling stream maybe configured to flow counter current to the feed stream in certainembodiments.

Alternatively, the swing adsorption process may involve sharing one ormore of the manifolds and associated valves. Beneficially, thisconfiguration may be utilized to lessen any additional valves orconnections for startup mode for adsorbent bed unit configurations thatare subject to space limitations on the respective heads.

As noted above, the present techniques include various procedures thatmay be utilized for the swing adsorption process. The present techniquesmay include additional steps or mechanisms to manage the temperature,compositional, and pressure pulses associated with the transition ofstreams within the adsorbent beds between the steps in the cycle. Thepresent techniques may include including a cooling step to minimize thetemperature fluctuations in a stream being conducted away from the rapidcycle swing adsorption process. In other configurations, a system mayinclude a dampening system that may be used to minimize the temperaturefluctuations and/or compositional fluctuations in one or more streamsbeing conducted away from the rapid cycle swing adsorption processunits.

As an example, FIG. 3 is an exemplary flow chart for performing a swingadsorption process in accordance with an embodiment of the presenttechniques. In this flow chart 300, the swing adsorption process mayremove one or more contaminants and may be used to manage thetemperature fluctuations and/or compositional fluctuations in one ormore streams being conducted away from the rapid cycle swing adsorptionprocess units. For each of the adsorbent bed units, the swing adsorptionprocess involves performing various steps, as shown in blocks 302 to306, which is described as being performed for a single adsorbent bedunit for simplicity. Then, the streams from the adsorbent bed units maybe used with the downstream equipment, as shown in blocks 308 to 314.

The process begins by performing the swing adsorption process for theadsorbent bed units, as shown in blocks 302 to 306. At block 302, anadsorption step is performed for the adsorbent bed. The adsorption stepmay include passing a gaseous feed stream through the adsorbent bed toremove one or more contaminants from the gaseous feed stream and tocreate a product stream that is conducted away from the adsorbent bedunit. At block 304, a heating step is performed for the adsorbent bed.The heating step, which may be one or more purge steps may includepassing the purge stream through the adsorbent bed to create a purgeproduct stream that is conducted away from the adsorbent bed unit. Theproduct purge stream may include the external stream and a portion ofthe contaminants within the adsorbent bed. The product purge stream maybe intermingled with a fuel gas stream and may be used in a turbine.Further, the purge stream may be subjected to a heating step prior tobeing passed to the adsorbent bed. The heating step may heat theexternal stream to a temperature less than 550° F., less than 500° F.,less than 450° F. or less than 350° F., and may be greater than 50° F.of the gaseous feed stream temperature, greater than 100° F. of thegaseous feed stream temperature or greater than 250° F. of the gaseousfeed stream temperature. For example, the purge stream used during thepurge step may be a temperature in the range between 500° F. and greaterthan 50° F. of the gaseous feed stream temperature, in the range between450° F. and greater than 100° F. of the gaseous feed stream temperatureor 400° F. and greater than 200° F. of the gaseous feed streamtemperature. The heating of the purge stream may include passing thepurge stream through a heat exchanger or similar heating unit toincrease the temperature of the purge stream. At block 306, the coolingstep may optionally be performed with the adsorbent bed. The coolingstep may include passing a stream of gas to cool the adsorbent bed. Thecooling step may include which may be a recycled stream that passesthrough heat exchangers or a refrigeration system to conduct away heatfrom the recycled stream. The process may repeat the step 302 to 306 foranother swing adsorption cycle.

After being processed, the streams from the adsorbent bed units may beused with the downstream equipment, as shown in blocks 308 to 314. Atblock 308, the product stream may optionally be measured. The productstream may be measured by a temperature sensor and/or a gaschromatograph or using another gas component analysis equipment. Theproduct stream may also be measured by taking samples, using a moistureanalyzer. Then, at block 310, a determination may be made whether theproduct stream is within the respective specification. The determinationmay include analyzing the product stream to determine the level of oneor more of the temperature, pressure, composition and any combinationthereof. If the product stream is within specification (e.g.,contaminants are at or below a specific threshold), the product streammay be passed to downstream process, as shown in block 314. However, ifthe product stream is not within specifications, the product stream maybe passed to the dampening system, as shown in block 312. The dampeningsystem may include a heat exchanger, conduits, an accumulator and/or amixing unit. The downstream processes may include a CFZ process, acryogenic NGL recovery process, or an LNG process, with the associatedequipment for each.

By way of example, the present techniques may include additional stepsor mechanisms to manage the temperature, compositional, and pressurepulses associated with the transition of streams within the adsorbentbeds between the steps in the swing adsorption cycle. In particular, themethod may be used to minimize the temperature and/or compositionalfluctuations in a stream through the use of cooling steps in the rapidcycle swing adsorption process, which is shown in FIGS. 4 to 6.

FIG. 4 is an exemplary diagram of a swing adsorption system 400 inaccordance with an embodiment of the present techniques. In thisconfiguration, a cooling step is used to manage the fluctuations in thestreams from the swing adsorption system 400. In the swing adsorptionsystem 400, a first adsorbent bed 404 is shown performing an adsorptionstep with the feed stream in a feed conduit 402 that is passed throughthe first adsorbent bed 404 and conducting a product stream away fromthe first adsorbent bed 404 via product conduit 406. A second adsorbentbed 410 is shown performing a cooling step with the cooling stream in apurge conduit 408 that is passed through the second adsorbent bed 410and conducting a cooling product stream away from the second adsorbentbed 410 via product conduit 412. A third adsorbent bed 416 is shownperforming a heating step or regeneration step with the purge stream inthe purge conduit 408 that is passed through a heating unit 414 and thento the third adsorbent bed 416 and conducting a purge product streamaway from the third adsorbent bed 416 via the product conduit 412. Afourth adsorbent bed 418 is shown in a stand-by with no streams beingpassed through the fourth adsorbent bed 418.

In this configuration, the purge stream (which may near the ambienttemperatures) is split into two different streams. The first stream isheated in the heating unit 414 and used to regenerate a spent thirdadsorbent bed 416, while the second stream is used to cool a recentlyregenerated adsorbent bed 410. These streams may be introduced in acounter-current direction to the feed stream which maintains the drynessof the product end of the adsorbent bed throughout the regeneration stepand cooling step. In this configuration, the cooling stream may not berecycled back to the swing adsorbent system be used as a purge stream.To regenerate an adsorption bed, the purge stream is largely devoid ofthe contaminant being removed. The cooling stream may contain asignificant amount contaminant. As such, it cannot be recycled as apurge stream. The cooling step may be part of the overall regenerationprocess, such that a larger amount of contaminant is removed, whilepurging in this regeneration step and a smaller (but not insignificant)amount of contaminant is removed, while purging in the cooling step.

FIG. 5 is an exemplary diagram of a swing adsorption system 500 inaccordance with an embodiment of the present techniques. In thisconfiguration, a different cooling step is used to manage thefluctuations in the streams from the swing adsorption system 500. In theswing adsorption system 500, a first adsorbent bed 504 is shownperforming an adsorption step with the feed stream in a feed conduit 502that is passed through the first adsorbent bed 504 and conducting aproduct stream away from the first adsorbent bed 504 via product conduit506. A second adsorbent bed 510 is shown performing a cooling step withthe cooling stream in a purge conduit 508 that is passed through thesecond adsorbent bed 510 and conducting a cooling product stream awayfrom the second adsorbent bed 510. A third adsorbent bed 514 is shownperforming a heating step or regeneration step with the purge productstream that is passed through a heating unit 512 and then to the thirdadsorbent bed 514 and conducting a purge product stream away from thethird adsorbent bed 514 via the product conduit 516. A fourth adsorbentbed 518 is shown in a stand-by with no streams being passed through thefourth adsorbent bed 518.

In this configuration, the purge stream (which may be at or near ambienttemperatures) is first passed in a co-current direction to the feeddirection of the feed stream to cool a recently regenerated secondadsorbent bed 510. The cooling step lessens the temperature of thesecond adsorbent bed 510, while recovering some of the heat in thesecond adsorbent bed 510. The resulting gas stream is then heated andintroduced to a spent third adsorbent bed 514 to regenerate the thirdadsorbent bed 514. This configuration has the additional advantage ofrecovering some of the heat from the regeneration process. In certainconfigurations, the purge gas exiting the adsorbent bed after thecooling step is largely devoid of contaminant as the purge gas isflowing along the feed direction. In other configurations, the purge gasstream may be in fluid communication (e.g., tied to) with an LNGdehydration process. In such configurations, the source of the purge gasstream may be adjusted to provide enhancements. Additionally, thecooling process may be continuous (e.g., at least one adsorbent bed thatis being cooled at any instant of time).

FIG. 6 is an exemplary diagram 600 of product gas temperature from aswing adsorption process. In this diagram 600, the temperature response606 is shown along a temperature axis 604 in Celsius (C) and a cycletime axis 602 in seconds (s). An example for the second configuration,as shown in FIG. 5, the temperature swing of the product end is dampenedfrom 175° C. to 29° C. (e.g., no cooling step) from 39° C. to 29° C. Theadditional dampening may be achieved by operating multiple adsorbentbeds out of sequence on feed. For example, a new adsorbent bed may beintroduced on feed, while a different adsorbent bed is alreadyoperational and producing product at nearly the feed temperature.

In one or more embodiments, the material may include an adsorbentmaterial supported on a non-adsorbent support. The adsorbent materialsmay include alumina, microporous zeolites, carbons, cationic zeolites,high silica zeolites, highly siliceous ordered it) mesoporous materials,sol gel materials, aluminum phosphorous and oxygen (ALPO) materials(microporous and mesoporous materials containing predominantly aluminumphosphorous and oxygen), silicon aluminum phosphorous and oxygen (SAPO)materials (microporous and mesoporous materials containing predominantlysilicon aluminum phosphorous and oxygen), metal organic framework (MOF)materials (microporous and mesoporous materials comprised of a metalorganic framework) and zeolitic imidazolate frameworks (ZIF) materials(microporous and mesoporous materials comprised of zeolitic imidazolateframeworks). Other materials include microporous and mesoporous sorbentsfunctionalized with functional groups. Examples of functional groupsinclude primary, secondary, tertiary amines and other non protogenicbasic groups such as amidines, guanidines and biguanides.

In one or more embodiments, the adsorbent bed unit may be utilized toseparate contaminants from a feed stream during normal operation mode.The method may include a) passing a gaseous feed stream at a feedpressure through an adsorbent bed unit having an adsorbent contactor toseparate one or more contaminants from the gaseous feed stream to form aproduct stream, wherein the adsorbent contactor has a first portion anda second portion; b) interrupting the flow of the gaseous feed stream;performing a depressurization step, wherein the depressurization stepreduces the pressure within the adsorbent bed unit; c) performing anoptional heating step, wherein the heating step increases thetemperature of the adsorbent bed unit to form a temperature differentialbetween the feed end of the adsorbent bed and the product end of theadsorbent bed; and d) performing a cooling step, wherein the coolingstep reduces the temperature within the adsorbent bed unit; e)performing a re-pressurization step, wherein the re-pressurization stepincreases the pressure within the adsorbent bed unit; and repeating thesteps a) to e) for at least one additional cycle.

In one or more embodiments, when using RCTSA or an integrated RCPSA andRCTSA process, the total cycle times are typically less than 600seconds, preferably less than 400 seconds, preferably less than 300seconds, preferably less than 250 seconds, preferably less than 180seconds, more preferably less than 90 seconds, and even more preferablyless than 60 seconds. In other embodiment, the rapid cycle configurationmay be operated at lower flow rates during startup mode as compared tonormal operation mode, which may result in the cycle durations beinglonger than the cycle durations during normal operation mode. Forexample, the cycle duration may be extended to 1,000 seconds for somecycles.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrative embodiments are only at preferred examples of the inventionand should not be taken as limiting the scope of the invention.

1. A process for removing contaminants from a gaseous feed stream with aswing adsorption process, the process comprising: a) performing anadsorption step, wherein the adsorption step comprises passing a gaseousfeed stream through an adsorbent bed unit to remove one or morecontaminants and produce a product stream; b) interrupting the flow ofthe gaseous feed stream; c) performing a heating step, wherein theheating step comprises passing a heating stream through the adsorbentbed unit to remove one or more contaminants from the adsorbent bed unit;d) performing a cooling step, wherein the cooling step compriseslessening the temperature of an adsorbent material in the adsorbent bedunit by passing a cooling stream through the adsorbent bed unit; and e)repeating the steps a) to d) for at least one additional cycle in theswing adsorption process.
 2. The process of claim 1, wherein theduration of the cycles is for a period greater than 1 second and lessthan 600 seconds.
 3. The process of claim 2, wherein the gaseous feedstream is a hydrocarbon containing stream having greater than one volumepercent hydrocarbons based on the total volume of the feed stream. 4.The process of claim 3, wherein the gaseous feed stream compriseshydrocarbons and carbon dioxide (CO₂), wherein the CO₂ content of thegaseous feed stream is from about 200 parts per million volume to about2% volume of the gaseous feed stream; and the swing adsorption processis configured to lower the CO₂ in the product stream to less than 50parts per million.
 5. The process of claim 3, further comprising passingthe product stream to a downstream process selected from a liquefiednatural gas (LNG) process that comprises an LNG process unit, and acryogenic natural gas liquefaction (NGL) process having a NGL processunit.
 6. The process of claim 2, wherein the cooling stream is passedfrom the adsorbent bed unit to a conditioning unit to produce aconditioned stream; and the conditioned stream is passed from theconditioning unit to an additional adsorbent bed unit as the heatingstream.
 7. The process of claim 6, wherein the heating stream is passedthrough the adsorbent bed unit in a direction that is counter-current tothe direction that the feed stream is passed through the adsorbent bedunit; and the cooling stream is passed through the adsorbent bed unit ina direction that is counter-current to the direction that the feedstream is passed through the adsorbent bed unit.
 8. The process of claim6, further comprising splitting a purge stream into the heating streamand the cooling stream, wherein the cooling stream is passed through theadsorbent bed unit in a direction that is co-current to the directionthat the feed stream is passed through the adsorbent bed unit; and theheating stream is passed through the adsorbent bed unit in a directionthat is counter-current to the direction that the feed stream is passedthrough the adsorbent bed unit.
 9. The process of claim 6, furthercomprising determining whether the product stream is within anacceptable temperature limit, and the acceptable temperature limit isselected from: wherein the product stream temperature is within about50° F. of the temperature of the gaseous feed stream; wherein theproduct stream a temperature is within about 25° F. of the temperatureof the gaseous feed stream; and wherein the product stream temperatureis within about 10° F. of the temperature of the gaseous feed stream.10. The process of claim 6, wherein the swing adsorption process is arapid cycle temperature swing adsorption process or a combined a rapidcycle temperature swing adsorption/rapid cycle pressure swing adsorptionprocess. 11.-25. (canceled)